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[structure: see text] Diastereomeric biaryl diphosphine ligands 10 and 11 with added chiral centers on the backbone were synthesized. Substrate-directed asymmetric synthesis occurred in the coupling step of the preparation of the diastereomeric diphosphine oxides. The diastereomeric diphosphine oxides were easily separated by column chromatography with(More)
Parkinson's disease (PD) is the second most common neurodegenerative disease affecting people over age 55. Oxidative stress actively participates in the dopaminergic (DA) neuron degeneration of PD. Xyloketals are a series of natural compounds from marine mangrove fungus strain No. 2508 that have been reported to protect against neurotoxicity through their(More)
Harmine, a naturally occurring β-carboline alkaloid, showed good antitumor activities together with remarkable neurotoxic effects in animal models. In order to search for novel leading compounds endowed with better antitumor activities and less neurotoxicities, a series of harmine derivatives were designed and synthesized by modification of position-2, 7(More)
In this work, we designed and synthesized a series of amide derivatives (1-13), benzoxazine derivatives (16-28) and amino derivatives (29-30) from xyloketal B. All 28 new derivatives and seven known compounds (14, 15, 31-35) were evaluated for their protection against H2O2-induced HUVEC injury. 23 and 24 exhibited more potential protective activities than(More)
A series of novel N(2)-alkylated quaternary β-carbolines was synthesized by modification of position-1, 2, 7 and 9 of β-carboline nucleus with various alkyl and arylated alkyl substituents, and their cytotoxic activities in vitro and antitumor potencies in mice were evaluated. Compound 3m was found to be the most potent antitumor agent. SARs analysis(More)
Essentially complete atropdiastereoselectivity was realized in the preparation of biaryl diphosphine dioxide by asymmetric intramolecular Ullmann coupling and oxidative coupling with central-to-axial chirality transfer. A bridged C(2)-symmetric biphenyl phosphine ligand possessing additional chiral centers on the linking unit of the biphenyl groups was(More)
An interesting rhodium-catalyzed asymmetric aqueous Pauson-Khand-type reaction was developed. A chiral atropisomeric dipyridyldiphosphane ligand was found to be highly effective in this system. This operationally simple protocol allows both catalyst and reactants to be handled under air without precautions. Various enynes were transformed to the(More)
A series of chiral diphosphine ligands denoted as PQ-Phos was prepared by atropdiastereoselective Ullmann coupling and ring-closure reactions. The Ullmann coupling reaction of the biaryl diphosphine dioxides is featured by highly efficient central-to-axial chirality transfer with diastereomeric excess >99%. This substrate-directed diastereomeric biaryl(More)
A series of novel chiral-bridged atropisomeric monophosphine ligands were synthesized via convenient and simple pathways. The prepared ligands, especially for ligand 7d, were found to be highly effective in the Pd-catalyzed Suzuki-Miyaura coupling reaction. The steric hindrance and electronic effect of substrates on the reactivity and enantioselectivity(More)
A series of bivalent β-carbolines with a spacer of three to ten methylene units between the indole nitrogen was synthesized and evaluated as antitumor agents. The results demonstrated that compounds 18c, 21b, 25a and 31b exhibited strong cytotoxic activities with IC(50) value of lower than 20 μM against four tumor cell lines. Acute toxicities and antitumor(More)